The examination of the coating and of open cooling-air holes on turbine blades is realized by means of an infrared camera. This involves excitation by means of hot air and flash lamps and recording of the resultant heat flux by an infrared camera. In order to examine suitable regions and/or image portions, the component, such as for example a turbine blade, and the camera must be correspondingly positioned.
A known testing system is described on the basis of FIGS. 1 and 2. In the case of the known testing system, the infrared camera is positioned by means of an industrial robot. The turbine blade is fixed on a rotary table. The rotary table usually has two receptacles for turbine blades, which are arranged such that one receptacle is located in an enclosure of the robot for testing while the other receptacle is externally accessible for the loading or removal of the turbine blade.
The tester's working place, located outside the enclosure, is shielded from flash and flow noises. In a testing procedure, firstly the type of test, the testing position and the focus of the infrared camera are established. Then, the parameters are transferred into a system database. The robot travels over a testing path, in order in this way to position the infrared camera.
WO 98/05949 A1 discloses a testing system for testing gas turbine blades for delamination, with a rotating device for the blade and a three-axis positioning device for an IR camera. To check the internal structure, hot air may be introduced into the blade.
EP 1 739 409 A1 discloses a testing system for determining the location and the angular position of holes in a turbine blade, with a fixed-in-place receptacle for the blade, a positioning device for an IR camera and a radiant heater for heating the turbine blade.
US 2008/237466 A1 discloses a testing system for determining the gas flow through holes in a turbine blade, with a fixed-in-place receptacle for the turbine blade and an IR camera arranged on a robot arm. Warm air is passed through the receptacle and through the turbine blade.
WO 03/038403 A2 discloses an inspection system for a turbine blade, with a fixed-in-place receptacle for holding and introducing air or gas into the turbine blade. A number of mirrors are arranged around the receptacle, in order to make more than one side or edge of the turbine blade accessible to an IR camera.
U.S. Pat. No. 5,111,046 A discloses a device for the inspection of channels of a turbine blade, with a fixed-in-place receptacle for holding and introducing air or gas into the turbine blade and an IR camera for recording heating-up and cooling-down processes.